Teaching materials are the primary source of input in the language classroom. The potential of English language teaching (ELT) materials to preserves and transmit our culture, value, identity, and language make it significant for socio-cultural sustainability. The materials developed by the National Council of Education and Research Training (NCERT) are far and wide running study materials in primary and secondary schools in India. India exhibits a massive variety of cultures, customs, languages, and religious beliefs. The selection and development of apt materials is, therefore, a matter of serious deliberation. The centrally developed material, despite numerous benefits, often lacks in representing different groups of students, especially the backward and marginalized ones. The contents, in most cases, are representative of the mainstream. Therefore, the study suggests teachers developed supplementary materials to which learners from all the groups can relate. The researcher has taken the context of Jharkhand and illustrates self-developed supplementary materials prepared using contents from learners’ social and cultural backgrounds. The article offers various suggestions on how to develop such materials that could bring socio-cultural equity in the classroom, making a significant contribution to social sustainability.